A slew of emerging technologies are redefining the concept of "hydropower." For almost a century, hydro has been synonymous with river-killing dams. But now a range of "hydrokinetic" technologies that convert into electricity the kinetic energy of flowing water – rather than the potential energy in falling water – offer the hope that in future "sustainable hydro" could offer more than big hydro industry greenwashing.
The US National Hydropower Association has recently expanded its remit beyond the promotion of traditional dam-based hydro. It now defines hydropower as
the power of moving water [that] comes in many forms from conventional to new emerging technologies of ocean, wave, tidal and hydrokinetic energy
The latest hydrokinetic technology to have crossed my email is a fascinating invention that uses the principle of biomimicry – it imitates the swim strategy of a school of fish to draw power out of slow water currents to produce electricity. Read the press release and view the promo video from the University of Michigan.
Its always wise to treat announcements of new save-the-world technologies with a grain of salt. Many will prove uneconomic, others to have unforeseen environmental problems, and others to just not work under real world out-of-the-lab conditions. But there's enough money and inventiveness going into the new hydro techologies that it seems reasonable to believe that they will form an important part of the sustainable energy future.
Two of my other favorites among the numerous hydrokinetic technologies in development are the SeaGen tidal current generator (a 1.2 MW prototype has been installed just off the scenic Northern Irish village of Portaferry in the "Narrows" where Strangford Lough meets the Irish Sea – very near where I grew up) and the Linear HydroEngine invented by International Rivers supporter Daniel Schneider.